Molecular motion in poly-2,5-difluorostyrene determined by nuclear magnetic resonance

The NMR of Polymers

“…The conclusions drawn in this work were confirmed by a subsequent study of the NMR spectra of poly-para-fluorostyrene (I) [322] and poly-2,5-difluorostyrene (II) [35]:…”

Correlated Segmental Dynamics in Amorphous Atactic Polystyrene: A Molecular Dynamics Simulation Study

“…Usually this process is attributed to the rotational vibration of backbone segments, 2 but some authors have assigned the process to the rotations of side phenyl groups. 13 The peak merges into the R peak at high frequencies. 2 Mechanical-relaxation 1 and NMR experiments 14 revealed additional γ and δ processes associated with oscillatory motions of the side phenyl groups.…”

“…Relaxational processes in amorphous PS in the vicinity of T g have been studied experimentally by dynamic mechanical, 1-3 quasielastic neutron scattering, 4,5 dielectric, [6][7][8][9][10][11][12] and NMR techniques. [13][14][15][16] It is an established fact that above the PS glass-transition temperature (T g ) 373 K), the R-relaxation is the primary relaxation process of collective segmental motion, 32 and the temperature dependence of the characteristic relaxation times is well described by WLF equation. 33 Immediately below (when decreasing temperature) the primary relaxation, there is another, so-called process, which appears in both dynamic mechanical and dielectric experiments.…”

“…Investigation of local dynamical properties of amorphous polymers has been a subject of many studies, both experimental [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] and by means of computer simulation. [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] Nevertheless, questions concerning mechanisms of segmental mobility in the vicinity of the glass transition still remain open.…”